1. Headache Science Center, C. Mondino National Neurological Institute, Pavia, Italy
2. Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway
3. Norwegian Advisory Unit on Headaches, St Olavs University Hospital, Trondheim, Norway
4. Department of Pharmaceutical Sciences, Università del Piemonte Orientale ‘A. Avogadro’, Italy
5. Headache Group – NIHR-Wellcome Trust King’s Clinical Research Facility, King’s College London, UK
6. Department of Brain and Behavioural Sciences, University of Pavia, Italy